The aeronautical sector is one historically marked by continuous demands for innovation and technological progress. The search to reduce the environmental impact of air transport, emissions of greenhouse gases and noise, naturally falls within this remit.
Rotary wing aircraft are known for their high greenhouse gas emissions per passenger per kilometer.
Future regulations will dictate compliance with increasingly low emission levels which is why there is a need to improve the efficiency of the propulsion system in order to reduce pollutant emissions.
As far as optimizing the propulsive part of helicopters is concerned, projects connected with improving the efficiency of the turbine engines have allowed certain performance improvements. Other projects connected with hybridizing the helicopter by considering various architectures means that additional improvements can be envisioned.
However, the electrical energy used for hybridizing is generally stored in batteries the weight of which penalizes the fuel consumption and available payload.
As far as the auxiliary circuits, electric circuits, hydraulic circuits and/or pneumatic circuits are concerned, energy is tapped off the auxiliary gearbox or the main transition gearbox (MGB) which means that fuel is consumed in order to power these systems.
Energy recuperation is, at the present time, very well developed for stationary applications such as cogeneration.
In the scope of hybrid helicopter projects, mechanical/electric hybrid rotor designs or even all-electrical rotor designs show a great deal of promise. These are architectures in which the mechanical power required is supplied in full or in part by an electric motor.